186 



THE AGKICULTURAL NEWS. 



Ju-N-E 16, 1917. 



INSECT NOTES. 



SOME WEEVILS OF THE GENUS 



DIAPREPES IN THE WEST 



INDIES. 



The weevils of the genus Diaprepes found in the West 

 Indies are of great interest both from the systematic as well 

 as the economic stand-point. For the last few years they 

 have been studied by specialists both at the Imperial Bureau 

 of Entomobgy in London, and at the Bureau of Entomolojjy 

 at Washington, and it has been considered that the ditferent 

 forms occurring in these islands would prove to be merely 

 local varieties, which could be grouped under one or two 

 species. From time to time collections of these weevils, 

 which are the adults of the root borer grubs, have been sub- 

 mitted by Mr. H. A. Ballou, Entomologist on the staff of the 

 Imperial Department, to Mr. W. D. Pierce of the Bureau of 

 Entomology at AVashington. These collections included not 

 only the brightly coloured striped specimens known as Dia- 

 prepes abhreviaiiis and D. spengleri, but also the uniformly 

 . dark, greyish-brown weevils belonging to the genus Exoph- 

 thalmus, and known in these islands as the Leeward Islands 

 root borer. 



Mr. Pierce recently sent back to the Imperial Depart- 

 ment a representative collection of these weevils from most of 

 the Lesser Antilles, to which he has added specimens of the 

 varieties occurring in Santo Domingo and Porto Rico. For 

 the sake of convenience lhe.se insects have been grouped as 

 varieties of two species of Diaprepes, the Z>. abbreriatus and 

 D. spengleri forms being placed under Diaprepes abbreriatus, 

 ■while the Exoplithaliiius group is put under Diaprepes 

 ^jamelicus. 



To the writer's knowledge ilr. Pierce has not yet pub- 

 lished any detailed descriptions of these species and their 

 •varieties under this new arr^mgement, although a paper by 

 lim in the Journal of Agricultural Research, Vol. IV, No. 3, 

 about two years ago, has reference to some of these varie- 

 ties under a different grouping. The subsequent acquisi- 

 tion of more material of this group from these islands 

 has. enabled Mr. Pierce to rearrange the varieties to 

 greater advantage, and further modifications may prove to be 

 necessary after a still larger series of these weevils has been 

 examined. It will be noticed that in each case a third 

 scientific name is used to designate the particular variety. For 

 instance, the full name of the variety of Diaprepes abbreviatux 

 which occurs in Barbados is Diaprepes abbreviatus distingu- 

 endiis, and that of the Antigua variety of Diaprepes famelicus 

 is Diaprepes Jamelicus esuriens. 



A table is appended giving the name and locality of 

 each variety as determined by Mr. W. D. Pierce. 



In addition to the varieties given belovv, there are in the 

 collection of the Imperial Department specimens from Nevis 

 and from Grenada, which have not been definitely named. 

 The Grenada .specimens come under D. abbreviatus, while the 

 specimens from Nevis belong to the D. famelicus group. A 

 form closely resembling the Antigua variety esuriem: is known 

 to be present in Barb:- ''os. 



J.C.H, 



SOIL GRUBS IN THE WEST INDIES. 



This is the time of the year when many soil-inhabiting 

 grubs, which are known as pests of some crops in these Islands, 

 are completin'; their life-cycle and emerging as adult beetles. 

 These insects have been the subject of various articles in the 

 Agricultural ]\'ew>: and are fully dealt with in Pamphlet 

 No. 73, is.sued in 1013 by the Imperial Department. Further 

 details appeared in the Agrindtural News for April 10, 1915 

 (Vol. XIV, No. 338). These pests are well known to the 

 Agricultural Officers and to the planters in the ditferent 

 islands, but the importance of these insects both in the grub 

 and adult stages, and the methods of control known at the 

 present time cannot be emphasized too often. These insects 

 are usually grouped under the two main headings, root 

 borers and hard backs. 



ROOT BOREF.s. 



The insects generally known as root borers in these 

 islands are now considered to be so closely related to each 

 other that they can be grouped together as varieties of two 

 species of the genus Diaprepes, viz.. D. abbreviatus and 

 D. famelicus (see the above table) 



Root borers are attracting more and more attention each 

 year as pests of such widely different crops as sugar-cane, 

 Indian corn, limes, cotton, sweet potatoes, onions, ground nuts, 

 etc., as is shown by the reports of the Agricultural Officers in 

 the various islands during the past few years. The exact 

 variety of root-bor^^r grub responsible for the injury is not 

 known in every case, but the nature of the injury appears to 

 be similar where the same plants are attacked in the ditferent 

 i.slands. For instance, the injury done to mature sugar-cane 

 in St Kitts by the local variety of root borer has been found 

 to be exactly siniilar to the injury done to the same plant by 

 the variety of root borer in Barbados. The above table will 

 show that the St. Kitts variety is closely related to the 

 Barbados variety. 



The feeding habits and life-history of the Barbados 

 variety of Dinprnpes abbreviatus have been worked out in 

 considerable detail, and the knowledge that we have about 

 the Barbados suLVir cane root boier will be of great assistance 

 when dealing with the closely related forms in the other 

 islands. 



